1. Field of the Invention
This invention relates to resealable closure assemblies that can provide rapid access to the contents of a container through a spout, without fully disengaging the closure from the container neck.
1. Description of Related Art
Closure assemblies for sports drinks are known, in which the closure is provided with a drinking spout and the assembly can be opened using one hand or by using the teeth.
Existing closures of this type include so-called push-pull closures. Typically, such closures comprise a main cap having a central opening in communication with the bore of a spout. The spout has a plug member that partially blocks the top of the bore. A top cap, also having a central aperture is mounted on the spout. The top cap is normally moveable axially between a first position and a second position. In the first position, the aperture in the top cap is sealed by the plug member, sealing the container. In the second position, the top cap aperture is not sealed by the plug member, allowing the container contents to exit the container around the plug member and through the aperture in the top cap. Closure assemblies of this type are described, for example, in WO00/64774. They have found wide application in fields outside sports drinks, for example on bottles of washing up liquid.
Certain other sports drink closures have an alternative configuration in which the pour spout can be opened by twisting. DE-A-4328582 describes such an arrangement
However, these closures have a number of problems associated with them. One problem is the fact that the flow rate around the plug when the closure is in the open position can be inadequate.
In addition, the previously known spout closures often do not provide effective sealing at the juncture between the spout opening and the plug positioned in the opening when the spout is closed. This is because the closure is held in the sealing position only by frictional forces, and can work loose to allow leakage of the contents. This lack of efficient sealing also means that the standard push-pull closures are not effective for use on containers containing carbonated drinks. The seal formed by the closure is not sufficiently tight to prevent loss of gas from the container between filling and consumption, nor to prevent gas escaping once the container has been opened for the first time and then resealed for later consumption. Also, internal pressure caused by carbonisation would tend to open existing closures thereby causing leakage.
A further drawback of existing sports closures is that it is difficult to incorporate tamper-evident features. For example, GB-A-2264110 describes a tamper evident ring for such an assembly, but it is apparent that excessive force would be needed to achieve reliable separation of the ring in use.
It would also be desirable to provide a convenient sports drink closure assembly that can incorporate the pressure safety features for use with carbonated beverages that are described and claimed in WO95/05322, WO97/21602 and WO99/19228.